Im sure that there are other micro-organisms are out there and even common. When we do find these it will be one of the most significant times in our history, when we realize that we arent alone.
This will pale in comparison to find intelegent life, that we will hopefully be able to converse with. If this ever occurs, our knowladge would grow exponentaly as we learn about each other.
Although, depending on who finds who, it could be problamatic for us. It is human nature, and i belive to be every inteligent beings nature, war and conflict advance civilization fastest. Look at how far planes came from the begining of WWI to the end of WWII, or how the cold war brought us to space. IMO any advanced civilization would be a violent civilzation. Ive never seen the hippies planning a space mission, but we seem to think, or mabye just hope, that this is how other civilzations will be. No advanced civilization would come in peace. only to conquer.