In the tweet, Welker stated that he "love the game" and his teammates and that "hopefully doing the right thing gets the right results." Clearly, Welker is signing the tender in good faith that the two sides will continue to work out a long term extension.
From a fan perspective, this is awesome news. Not only does it get the team's top receiver and Tom Brady's favorite option under contract for at least one more year, but it shows fans exactly how committed Welker is to the team. For the Patriots organization, having Welker under contract gives the team a lot more leverage in negotiations. Welker will now be required to show up for training camp and mandatory mini-camp (in June), or he will be sacrificing part of his $9.5 million salary. The team no longer has as much urgency to get a deal done. At the same time, should they fail to extend Welker, it would qualify as a bad PR move since Welker has taken this "leap of faith," as he described it.
For Welker, there is not much to gain from this move from a financial perspective. He's played into the Patriots hand in that sense. Nonetheless, this move shows a renewed commitment to the team and will allow him to get into team workouts and OTA's, acclimate with the team's new additions and make the necessary preparations to have a successful 2012 season.