If the buzz among attendees of last week's Google I/O conference in San Francisco revealed a common thread, it was that the search giant's ongoing push for developer mindshare remains intriguing, though rife with questions and concerns.

And though growing pains are to be expected, the tenor of the talk on the conference floor highlighted notable misgivings about the direction Google is outlining for developers as it pushes deeper into the enterprise development realm.

Roger Simmons, a Java EE architect at consulting firm Purpleshift and one of the 3,000 attendees on hand, sees the Google App Engine application hosting service, the company's Gears technology for mixing Web and desktop capabilities, and its data APIs as the locus of Google's enterprise development play.

[ For an in-depth look at Google App Engine, see "First look: Google's high-flying cloud for Python code" ]

"They're becoming a platform for enterprise software development," Simmons noted, before expressing disappointment with the current limitations of technologies, especially App Engine's Python-only support.

According to Simmons, before App Engine can be taken seriously, it will have to add support for Java and Groovy as well. Google has expressed intentions to expand the base of languages supported on App Engine but has not yet revealed a time line. And therein lies Google's enterprise development promise in a nutshell: early efforts with significant upside and buzz awaiting full-blown execution of intentions.

Concerns about the core
Of course, getting a bead on Google's intentions is not always easy. Perhaps because of this, attendees levied criticisms against the lack of development hooks Google has provided into its core AdWords advertising technology -- likely one of the chief means for developers to monetize any Google-based offerings.

"Google is an ad company. They make 95 percent of their money off of ads," said Scott West, who is affiliated with In.Genu, an online seller of therapeutic products and Google AdWords customer. "Most of the stuff they're offering here [doesn't] give them the hooks to serve up that advertising."

West, who also owns engineering design company Descartes Technology, added that a Google representative in attendance went so far as to de-emphasize AdWords as a Google priority.

The conference, to an extent, "has forsaken me, the advertiser," West said.

Although he concedes Google does offer effective tools for serving ads, West said he would like see a more powerful ad engine from Google "that really reduces my maintenance time."

A Google representative, contacted after the conference, shrugged off the insinuation that advertising is no longer top of mind.