Google may be best-known as a search engine, but with more than 350m people actively using its Gmail service and more than 90m registered users on its Google+ social network, it’s clear that Google isn’t just a search engine.

Increasingly, that’s creating some tension as the Mountain View-based company uses search to promote its other offerings. Now, it appears that Google has turned to its signup form in its effort to boost usage of those offerings.

As reported by Alex Chitu at the Google Operating System blog, which is not affiliated with Google, it appears Google is testing a new version of its signup form that requires users to create Gmail and Google+ accounts at the time of signup.

While the old signup form is still available, and it appears that the new signup form is not in use universally, the mere fact that Google may be testing a form that requires new users to acquire a Gmail and Google+ account is sure to spark further debate about Google’s tactics, particularly with respect to how it’s seeking to grow its social network.

The EU’s antitrust probe was expanded to look at Google+, and the company’s Search, plus Your World roll-out caused some to suggest that Google was going too far in its effort to promote its own properties.

As a practical matter, Google naturally wants to maximize how many users interact with its products and experimenting with a signup form that ensures they their accounts include two of the most prominent and important makes sense. Needless to say, however, Google’s experiment may not pay off. A more involved signup process could reduce conversions, and it could also produce more inactive Gmail and Google+ accounts. Inactive accounts on the company’s social network might boost its registered user numbers, but they won’t help Google+ become a more vibrant, profitable Facebook competitor.