Solar activity affects the Earth every single day. Some days more than others and sometimes we notice is while we usually don't. The solar cycle is an 11-year process that leads the sun through a period of low and high solar activity. The next "high" is projected to be during 2013 after which the suns activity will decrease and start building up for the next 11 year cycle.
For comparison: Just this past week an X-class solar flare erupted from the sun facing earth. While scientists confirmed that the flare was powerful enough to disrupt radio and satellite communications on earth, we didnt notice a thing. X-class flares are one of the strongest types of solar flares that can be measured.