Wave, Knol, Gears and more.
To be honest I love that Google tries to innovate but you can't help but feel they get throttled by the fact that the only audience that really cares about most of their products is the tech community. Email aside, which everyone already used anyway, not many Google products seem to get much attention from Joe-public.
It seems to me like anything they do, the first reaction is going to be "how can I use this to get more traffic" because basically, that is what Google provides. Traffic.
The downside to all this is that Google is now investor-owned and all an investor wants to see is an ROI. With each product that costs to produce and doesn't generate income there will be more pressure to bring in cash through adverts and affiliate deals. Not only could that stifle Google's innovation but it means more direct competition for other businesses.
Saw a report yesterday that suggests G+ is on the wane too although after the predictable initial surge of interest that was bound to level out I'd have thought.