Guest blogging as a link building strategy is not a good idea. In 2014 Google started penalizing blog networks and guest bloggers. Google has now officially added, "low-quality guest blog posts" to their list of guidelines violation.
Google's new social adventure is called Schemer. Google Schemer is fully integrated with Google+ and keeps fellow Schemers abreast of activities of other Schemers within their Google+ Circles. Schemers can create, share and do “schemes” with Google Schemer and keep others updated as to their progress. Anything can be a Scheme for example, ordering your favorite dish at a restaurant, flying a kite or dancing in the streets. With Schemer, Schemers can also find stuff to do anytime they're looking for activities. It's even possible to search for schemes and get or give a Heads Up about potential Schemes. Google Schemer users get credit for inspiring others via "Heads Up" or inspiration credit if other users discover schemes through your Profile page, through your scheme activity on their Home page or through links of schemes you share on sites such as Google+ and Twitter.