question about allowed content types...

I never intend to usurp the boundaries of a community on purpose, therefore I thought I should ask these so I understand for future reference:

1) "double-posting" cool? (i.e. two statuses in a row? I tried, but then my first was gone, did it automatically replace my first for that reason?)

2) trusted links ok? (eg. youtube. Some places auto-remove posts with links, and wonder if thats the culprit.)

Thanks. (* ^◇^)_旦