how would one read this type of genetic data, any useful sites?

I'm not really sure what you mean to ask by saying "how would one read this type of genetic data". It depends entirely on what you want to actually *do* with the information you're looking for.

For context, this is a genome browser. I'm not familiar with it, but there are probably commands that will allow you to "browse" to a specific point on the chromsome and look for what's at that location. I just looked it up myself, and it contains the locus for interleukin 17A, (which is that black bar at the top - the thick black lines are exonic sequence, the barred line will be introns. I'm not immediately sure what the thinner black bar signifies. If you click on that (anywhere on it) it will give you more information about that gene than you can possibly ever need - sequence, structure, references.

I have no idea what the little marks with the numbers are. You can alter what type of stuff the browser shows you, but it has, like, a billion of them and I'm not about to sift through to figure out what you've randomly turned on. The numbers are accession numbers - they're automatically assigned labels that are given to sequences which are automatically mapped onto the human genome sequence in this map. They may be sites with known polymorphisms. They may be sites where regulatory proteins bind to the sequence. They seem to be pretty small, but really, they could be anything. If you click on them, they'll probably tell you what they are - although you might not understand it. ;)

Just as a personal preference, I've always preferred Ensembl. http://www.ensembl.org/index.html - very similar, although it might not have all the tools you want. Here's the same stretch of DNA on Ensembl: http://www.ensembl.org/Homo_sapiens/Location/View?... - again, you can click through to find more information than you'll ever need about IL-17A.

Personally, I find genome browsers a little bit pointless myself - if I have a gene of interest, I'll just look it up (either on Ensembl - you can look up the genes by name, rather than trying to find them on the chromosome first! - or on something like uniprot). But then, I don't really work in genomics.