unfortunately this isn't a helpful reply - i'm just posting to say i've had the same question, and would also like to know how useful it's been to people.

From experience, I have never been contacted through my own site. I seem to get more offers from coroflot & linked in. I think it's pointless to design a portfolio website if you're only using it as a advertisement tool because chances are, not a lot of people would know your website address. You'd need to advertise the website in networking events or linking it to job sites such as linked in. 

If you're trying to get an architecture job, get your portfolio and profile set up on Archinect! There are TONS of firms looking for new hires here.

If you're looking for a web design job, design your own portfolio website, but then you will need to promote it to get people to see it.

I think that a lot of what I would do with the portfolio site would indeed be to link to it on social networking sites or include it on my resume/job applications as a way for people who already know about me to see more information about my work than could be contained in a social networking profile or a teaser pdf. In that respect I think that an Archinect profile would be a complementary rather than competing approach.

For what it's worth I should also share one of my experiences. There was a student who graduated from my undergraduate program a few years ago who has acquired a (slightly) legendary status among my classmates, based on the quality and uniqueness of his work and also where he was accepted to graduate school. He has a portfolio website, and I have been wondering how much that contributed to an awareness of his work - I personally first found about about him through a Google search that led to his website. However, he may have also gotten attention from doing and publicizing an unusual project (that was largely promoted online) and also from presenting at a well-attended alumni career panel. It's made me wonder how these systems of networking work, and if there is something which I could learn from his approach.

I made my own website and find it a nice tool to have. I also have some work my archinect profile, but I have had people looking for me (after meeting me) and finding my website before my linkedin. I am a total novice so it was fun learning the basics and designing my own website. It could certainly use some expert help, but it sounds like you already know how to design it. I would recommend doing it as it helps to stand out from the crowd. Sometimes its the little extra effort of making your own site vs an archinect or linkedin portfolio that impresses a client or employer

But yes, I only really get "traffic" on my website through networking.

I have found that blogging platforms provide a good balance between "off-the-shelf" format and functionality and the opportunity to customize appearance. tumblr, blogspot (Google blogging engine), and others are easy to have up an running with minimal time and effort. An added benefit is that these are free, and will show up in search engines.

I am not impressed by Linkedin's portfolio partner (Behance), but admit that I have not dug in to deeply to the capabilities of that system.

(I agree with others here that unless one's goal is to establish a footprint as a "firm", and really drive traffic to a website, the time & cost thereof may not provide value.)

I think having a portfolio website is absolutely worth it.  Its a great way to showcase some graphic/web design talent and its one of those skills that not everyone has. For potential employers, I send a small portfolio of work samples, and if they are interested enough to see more, they can visit my site.  Websites are easy to update and for me, it has been a great networking device.

I used a very simple flash-based platform that made it very easy to create a customized, professional looking site.  It's been cheap to host and took me just a few weeks to get up and going.  Only problem is its flash based-- wish I would have gone the HTML route.

www.gregoryzamell.ocm

Yeah, personal websites may not be the best way to get your name out there, but it's a fantastic tool to use as a means of keeping your status up-to-date. Since the majority of the world is going virtual anyways, might as well keep an online portfolio of your work!

I'm still working on mine. Haven't decided if I want to go flash or just stay HTML. As Gregory mentioned, there are problems with Flash (not all browsers facilitate it). And as everyone has alluded to, web design is a very marketable feature in your arsenal!

have you tried cargo collective?

it's pretty easy and the premium version is not very expensive. Is the one I use:

http://forgottenumbrellas.com/

(they let u use a custom URL)

@Amy Leedham
My thoughts exactly.  I had always been into web design and programming since grade school, so I always pursued my own website rather than using templates and other preformatted online portfolios.  Building and updating websites keeps me current with the presentation trends and marketing strategies needed to keep an online presence.  But it's the ability to stand out among the crowd with my own web domain and customized website that have impressed many clients and especially my employer. 

Like many have already mentioned, a big part of having one's own website is sharing it through networking and marketing it on online communities.  It's challenging at first, but once it's out there, the network works for you and continues to market your website.

I've gotten contacts through my personal website, as well as through design portals like Coroflot. 

In terms of return on investment, I would say that depends on what sort of designer you are marketing yourself as. If you're marketing yourself as an architect, then investing a lot of time in a super custom, bespoke website built from scratch would not be worthwhile. If you are marketing yourself as a web designer, then it's a requirement. On average, I would say the most return on investment comes from slight modification of an existing platform like wordpress or indexhibit that lets you upload new projects and change your information easily enough that you will keep things current, which is much more important that over the top personalization of the visual design. 

oh, and now that I've read some of the comments, I should mention that my website does manage to get independent traffic. Yes some of it comes from LinkedIn, Facebook, and Archinect, but I actually get more search traffic than referrals. Some people search for me by name, more by a project that's been pretty well publicized. So maybe that's a key—if you've gotten work published at all then a personal website is great for giving people more information on it and on you.

The only advice I can offer (based on my experience reviewing portfolio links that get sent to me) is this:

A) Make it simple, readable, and pretty,

B) Under no circumstances should it use Flash, Java, heavy Javascript or other embedded application environments (PDF links are okay, but also not great),

C) Try to optimize the display size and design for mobile devices, or have a separate site that automatically forwards for mobile devices (I usually wind up reviewing the things when I'm on the road ... you'd be surprised how many portfolio sites - and even professional firm sites - are completely unreadable on an iPhone)

If you decide to create your own portfolio website, make sure to focus on the content, and keep the design/framework of the site as lightweight as possible. If you're looking for an architecture job, the web design should be practically invisible. If it's a really nicely designed website, you'll probably be attracting employers who want to hire you for your web skills. If it's not a well designed website, it may frustrate an architecture employer looking at your portfolio.