How to interpret prevalence?

Hi everyone, I am wondering if you can help with interpreting some of these reports. Sometimes, I am not sure whether something is a major problem that happens all the time or something that has already been resolved.

1. I am seeing these graphs that show the last occurrence. Often, I will see that the last reported date in the graph is a long time ago. Great, that says to me that the bug is probably fixed. However, next to the report itself it says "Last seen: a few seconds ago." So do I worry about this or not?
   
   
   
2. Each bug has a list of affected OSes and a list of affected devices. Sometimes these have wide discrepancies. For example, I'm looking at a bug that lists a long, long list of OSes, but then it says under affected devices, Unique models: 2. So how do I judge what the impact is here?
   
   
   
   
3. Another useful data point would be a number of impacted users. It seems that with the collection of the other data, they must have this also, but I haven't figured out how to expose it on a per-bug report basis. This is possibly more of a feature request but it would be great to see that.
   
4. Is it possible to link to the reports? I want to turn them into tickets in Jira and link to the reports, but it looks like it's all AJAX on the reporting page with no way to link to them. It also makes it hard to come back to reports you've already looked at, and want to check the status on.

 

Each bug has a list of affected OSes and a list of affected devices. Sometimes these have wide discrepancies. For example, I'm looking at a bug that lists a long, long list of OSes, but then it says under affected devices, Unique models: 2. So how do I judge what the impact is here? I also have this problem.