If you’re using Google+, you might have noticed that unlike many other social networks (such as Facebook and Twitter) there isn’t an option to create a vanity URL. Instead, each profile is identified by a long string of numbers in the URL (for example, 107030912810704099919).
According to Mashable, the reason Google+ doesn’t offer its own vanity URL shorteners is to keep out spammers who could possibly use that data to infer account information about the user. Google+ isn’t a standalone product, and elements of the social network will be baked into various Google products (including search and gmail), so it’s obvious why the company is placing so much importance on privacy.