The Conundrum of Triangulation

I think I have 2 qualitative methods I can use for this dissertation. I plan to use content analysis and demographic survey. Now, it is called "triangulation," so I should use one more. Not sure what to choose though... interviewing? Focus group would be a bit difficult. And not sure if I can do field notes, unless I count how often people post and when. Not sure if that would contribute any to my data. It could though... Hmmm...