The time period between mid-2007 and late 2009 when Web2.0 tatics, platforms and ideals were waning, but Web 3.0 had not yet matured or went mainstream.
Both Pandora and Muxtape were shut down in Aug. '08 by the government. A sad casualty of Web 2.5.
The point of contemporary online usage between Web 2.0 and 3.0. Marked by greater integration, mobility and ubiquitous use. Also problems with adapting to newer methods while holding on to past ones.
All my social media post automatically go to my Twitter feed. Web 2.5 example at work.