MegaPath contracted with NorthPoint to use its DSL network. Neighbors are on the same line, meaning that speeds can diminish from heavy traffic. Doesn't depend on phone or cable company's limited reach, most of Bay Area is covered.
Many companies offer free installation and rebates on equipment.
DSL sends data over existing telephone lines, but many companies providing this technology are in financial trouble. Together, cable and DSL serve the vast majority of broadband subscribers. Two emerging options are fixed wireless and satellite. NorthPoint is not alone in its troubles. If your ISP went kaput, simply choose another service provider.