http://pioneerit.blogspot.com/2007/04/my-innoview-with-wayne-crosby.html

The following interview I found with one of the Zenter founders makes me think that Zenterr was acquired by Google in April or May, but stalled to announce it till now. I think most of Zenter is probably already integrated into google's system, and they are just polishing things out for launch. I basing that on the fact that google said their presentation app would come out in the summer, and the following statements from the Zenter founder back in an interview back in april:

"We have written 40k lines of code, filed 2 provisional patents, created several million dollars worth of value, and have **already talked to acquirers in this short time.**"

""In the short term, we are focused entirely on **getting Zenter out of private beta**. We have 88several media events that are scheduled for next month**, so more heads down coding until then. After that, the focus is going to be on building Zenter into a $100m company with growth''

They were working on getting out of beta, and was planning for media events. I think they got acquired in May, and continued there work transferring to Google's servers, and are almost finish.

http://pioneerit.blogspot.com/2007/04/my-innoview-with-wayne-crosby.html

If that's the case then why did Spreadsheet come out first? So Google though of something more complex (PPT) than the simpler (SSHEET)?

On the other hand your speculation may be true. Then they bought Tonic Systems again? Well I hope your speculation gets to be true... ;)