There is no evidence yet to suggest that profile links hurt your site. However, Matt Cutts has made some very telling statements about profile spam which clearly indicate that Google has a strong dislike for this particular type of link spam (and probably also means they still work).
Although they may not have integrated a way to deal with this type of spam into the algorithm yet all indications are that they will deal with this some time in the future.
Although we disagree with Google’s definition of link spam we do agree with them on this one.
Really, profiles created just for a backlink merely clog up the internet with useless empty garbage and are therefore truly spam in nature. They have no intrinsic value and offer nothing of interest to any internet user.
These profiles are created en mass for massive number s of backlinks on forums where no interaction takes place via those profiles.
In our opinion profile links should be avoided due to Google’s clear hatred of them and the fact that they just clutter up the World Wide Web.
If you must use profile links then you should do so only on sites were you actively participate.
Placing a link back to your site on a profile in a forum that you actively post to is fine but creating hundreds or thousands of profile pages spammed with your backlink is not a wise idea.
Your time and energies would be much better spent creating valuable web properties with good, informative and interesting content.
Placing a contextual link within the content of a related web property also holds much more value in the eyes of Google and will have a much bigger impact on your rankings anyway.
Blogs and Web 2.0 properties are an ideal way to do this.