If you are vain and thinks that Google+ ID is a pain to remember, Gplus is here to rescue you. Get a shortened address with Gplus. For example, I have done mine and you can see my profile now with http://gplus.to/joeteh
I don’t think this is affiliated to Google (means it is at your own risk) but it is nice to get some shortened URL (or you can try others like bit.ly and etc) that many will remember. Quick, before the user names are taken up.
Update: A check with Who.is indicates that GPlus.to link to IP location in Turkey.
Remember, Google+ ID are those numbers.. that you see on your Google+ account.