If you're talking about the typical mid/end-of credits cameos that these Marvel flicks do, I assume it is hinting towards a future movie.
The next Avengers is Age of Ultron, correct? And I do believe, without any real knowledge
is involved in this Guardians flick, or with the Guardians, anyhow.
Either way, the current Marvel IP, aside from the X-Men stuff, has been pushing all the stories to an ongoing plot with everyone involved. I'm still giddy over the Thanos appearance at the end of Avengers--now with Drax and Gamorra (not sure what has happened to them since the 90s), I'm hoping there is some Infinity something something in the works.
The only problem with the current IP, imo, is that Fantastic Four is still owned by whoever made those turds...and they also own Silver Surfer. I give a generous helping of shit what happens to the FF, but this keeps Silver Surfer in complete obscurity.