Have no first-hand experience, but someone asked this question of Chris Sacca (Google) at the first startup school, and he said:

"Don't worry about it. Use whatever you're most comfortable developing in. If we buy you, we'll likely have to rewrite all your code anyway to use Google's infrastructure and scale to millions of users."

So if your exit target is Google, you might as well save them time and increase your valuation by using Java and GWT.

Ugh :(

They'll still have to rewrite. The "infrastructure" he was referring to was GoogleFS/BigTable/MapReduce and their other massively-distributed backends. You don't have access to them if you aren't Google.

I've heard that GWT isn't actually used by any notable (= public has heard of it) Google project. Could be wrong though; no inside information.

What about Gmail and Calendars? I was under an impression that both of those use it. Maybe even Google Reader... not sure.

Gmail doesn't: http://news.ycombinator.com/item?id=56768. Dunno about Calendars or Reader.

Yes, but it is a hard thing to plan around. Can you really know who might want to buy you?

Good advice from an old boss: DO NOT include words like kludge, bug, garbage, or swear words in code or checkin comments. All production code has kludges, bugs, and fscking garbage in it but making it easy for a due diligence auditor to grep it can't help.

[True story, at MusicBlvd.com I was ordered to write a SUID root program to move html files from staging to production directories. I protested but wrote it anyway and named it kludge.c. After we were bought by CDNow I found out they had a SUID root bash shell on _every single frontend machine_. Kludge indeed.]

A startup I worked at received investment from a group of investors. While doing due diligence the investors said we made it easier for them because we were using Microsoft technologies. They turned out to be really bad investors who were real PITA.

I guess I am trying to say it only matters to people you probably don't want to do business with. They should care about how capable you are not the platform/language you chose to use as a tool to show your capabilities.

Just a data point: writely, which is now google docs, was originally based on .NET (on the server side):

http://scobleizer.com/2006/03/09/congrats-to-writely-for-usi...

Another Google data point: Steve Yegge ported Ruby on Rails to JavaScript because Google works in only 4 languages... C++, Java, Python, and JavaScript.

http://www.iunknown.com/2007/06/steve-yegge-por.html