What I have been experiencing is that when I open multiple threads in tabs, sometimes one of the tab pages loads with only the base stylesheet, the content is blank.
On that tab, if I try to load the next page of that thread, all subsequent pages in that thread load blank as well. If I click the link on that tab to go to my profile, it loads blank as well.
If I close the tab and click the thread from the index, it all loads fine.
I have seen where bandwidth throttling has caused this to happen on other sites.
Bandwidth costs money.
Lots of sites slow down their connection to save money.
Kinda makes sense for a free site that is under high load.
This incomplete page load is not constant.
It mainly occurs at certain times of the day and on active threads.
While it is a slight inconvience to me, its not terrible and since I kinda expect it now, not really a big deal.
You can test your internet speed using the speed test site
http://www.speedtest.net/
The thing to remember on slow or unresponsive sites is to check other sites to see if they are also slow.
If all sites seem to load slow, check your internet speed.
There are programs that allow you to optimize your internet speed.
For my PC I use
TCP Optimizer.
A quick google search for "internet speed optimizer for..." (add your interface device, iPhone, android, laptop, PS1, x-box, etc) will give you your choices.
You can also call your ISP and ask for a boost for your wifi (you may have to pay extra for that).