I do use web2.0s for all my SEO campaigns but they are only used to diversify the link profile. Alone web2.0s are not effective. Atleast this is the case for me.

Web 2.0 still active to create link building and get rank.

Links are still an integral part of the algorithm and web 2.0s are still effective, but their effectiveness mainly depends on the number and strength of the tier 2 backlinks you send to them.

They are excellent as buffer sites (and they are free) but make them look real with more than one post + images/videos. In this way they won't be deleted and you'll get more juice from them.
You can also make them powerfull via link funneling. You can see how that works here:
I’m KILLING It With This Completely New Kind of Backlink

Web 2.0 can work, but I think in competitive niches you will need stronger links than that. But they do have a place.