Getting pop-up advertisements? You shouldn't be.

The UBC Botanical Garden and Centre for Plant Research website is advertisement-free.

If you are receiving pop-up advertisements while you are browsing the site, then your computer has been infected with "spyware" or one of its cousins.

What is spyware? from the University of Illinois at Urbana-Champaign:

The University of Illinois website suggests a couple programs that you can use to remove spyware from your computer. It also makes the suggestion of turning your browser security settings to high (which will interfere with browsing the garden forums, especially if you are a registered user - see this thread for details on how to allow botanicalgarden.ubc.ca cookies).

Ways to decrease your risk of becoming infected with spyware and its cousins include using a modern web browser like Mozilla, being very cautious about any free software you might download (try to make sure it's from a trusted source) and using a non-Windows operating system. All other factors being equal, Windows still receives the lion's share of attacks / intrusions since it is the most popular OS. If you do use Windows and Internet Explorer, installing the available security patchs and updates is an excellent policy to follow: Start button -> Windows Update ought to take you right to the site on most systems.

To clean up spyware, consider using one of the software programs suggested on the UIUC site.