Slide has announced it will be closing, and the vast majority of it's products will be retired. Most of Slide's 100 person team will be integrated over to other Google products and could certainly bring value to Google+. Max Levchin, founder of Slide, and the product head Jared Fliesler will be leaving Google/Slide.
Photovine, Disco, Pool Party, Slideshow, SuperPoke! Pets, and Video Inbox will all be closed in the coming months. Even though these are closing I am sure their technology will be used elsewhere. It is being reported that Prizes.org will remain open.
Google bought Slide about a year ago and has allowed them to operate as an independent startup entity. None of their products really took off and with Larry Page continuing his streamlining the choice seems logical. The Google+ Project is really becoming the focus, and future!