You may think that having a strong profile in all places might be only for the hyperconnected so I have a strong suggestion: pick one and beef it up.
While many of us have accounts on multiple websites, social networks, and our employer's sites, very few people pay attention to the quality of their online presence and the ease with which they can be reached by a client or partner. We have discussed before how your profile is your ticket to getting connected with others online but we never addressed which profile is the most important. I honestly don't think there is a best one for everyone but here is some food for thought:
Really, this is the most important profile for professional people in the western world. Your profile on Linkedin is comprehensive showing me your volunteer activities, who you're connected with that I might be connected with, as well as the richest display of your education and experience. If you don't have a sizable inheritance and need to make a living from your connections to one or more people, you need to be on Linkedin. If you are in a B2B role, you might want to make this your main profile that you give the most attention to.
Google+
Put aside your opinions of love or scepticism for Google+ as a social sharing channel and pay attention to this: your Google+ profile feeds your Google search results and Google search is how most people still find pretty much everything online - including connections. It is also the best profile for linking to all of the other places you can be found online and it includes one of my all-time favorite profile features for understanding another person's perspective: where have I lived before. If you want people to find you easily you might want to make Google+ your main profile.
About.me
About.me is like an online business card or a central hub for all of your other profiles. It has competitors but it is the most popular profile-only account you can have that doesn't have a social network behind it. It is easy to get, simple to use, attractive, and adapts your profile to a variety of screen sizes well. If you are picking one main profile to focus on, this might not be it, but if you have more than a couple that you give attention to, this might be a good place to bring them all together. I use it for my main URL: jeffroach.ca
The largest, most influential social network on the planet has a lousy profile format that not a lot of people rely on to get to know someone new. Facebook's profile is loose, un-standardized and sloppy and geared more for friends who know each other well than for discovery of someone new. However, Facebook does feature more personal preference type of details that might paint an endearing picture for you if you want to be known more for your interests than your experience. Artists, curators, and culture-lovers can show their favorites of all things well on Facebook and that might be your strength.
With a bio of only 160 characters and only a few other details like location, web link, and not much else, your profile on Twitter is too short and simple to ignore. Beef up your profile on Twitter because it will only take you a few minutes. But don't expect your profile on this channel to satisfy the interests of a connection who is trying to get to know you better. I simply would not recommend using Twitter as your main profile online. Link from it to something more comprehensive.
There are countless third-party profiles you can focus on and beef up and some of them can be very important, especially if they are specific to your industry and widely used by your colleagues. But the ones mentioned above are the big ones, in my opinion.
We don't all have time to be everywhere online and we certainly can't manage to support an endless collection of perspectives on who we are, what we've done, and why others might want to get to know us better - or hire us. But everyone needs one main profile that makes it easy to find out who they are, what they've done, and how to connect with them right now. What is your main profile and are you happy with what others will find there?