ISPs are the big name companies, like Comcast, Verizon, AT&T, Sprint, etc., that offer you service and provide an on-ramp to the internet and email from your phone or wireless access for your laptop, or iPad. They tout claims of 3G (3rd generation cellular wireless), 4G (4th generation), etc., but the claims are not truly living up to the legal descriptions of those services. For instance, the original ITU-R requirements of data rates approximately up to 1 Gbits ( 1 gigabit = a billion bits per second) for 4G systems. Average phone users get speeds of about 1Mbps (1 thousandth of a Gbits) and the minimum is 400Mbps.
Bottom line, don't believe any of the hype. All providers these days are good enough, unless your are a power user and download large amounts of data or play games with users around the world. Be happy that, for the most part, we no longer have to rely on dial-up service for our home PCs.
Here is a site where you can test your speed. LINK It takes about 30 seconds and you can see how your home system compares to others. Below are my results with Verizon FIOS.
Google's internal studies show that introducing a delay of 100 to 400 milliseconds (thousandth of a second) when displaying search results led users to conduct up to 0.6 percent fewer searches.