Manufacturers are not required to offer warranties on their products and services, but they are required, per the Magnuson-Moss Act of 1975 to make their warranties understandable and enforceable if offered. That being said, whether or not a warranty is needed is probably determined more by the product itself than where it is purchased. There are, for example, any number of venues at which one might purchase a name brand vacuum cleaner such as Hoover: home improvement stores, discount stores such as Target and Wal-Mart, even retailers such as Sears and Best Buy, this in addition to any number of online retailers who might offer such a thing. Hoover is a reputable brand, and many consumers might feel comfortable purchasing a Hoover product without a warranty, while others might not for whatever reason; however, whether or not one desires a warranty would relate more to a person's comfort with a brand and how long he or she needs or wants it to last. More important to know as an online shopper might be a retailer's return policy and reputation, best gained by reading customer reviews if possible.
Due to the fact that so many consumers are able to do a large portion of their shopping online, retailers and manufacturers have increased the availability of warranties in order to make the consumer feel safer when buying products. The warranties themselves may be full of loopholes or be relatively limited, but it is the peace of mind that comes with the idea of having a warranty that it is important...most warranties that are offered are rarely used by the consumer.
Yes, I would say the availability of companies having warranties over things such bought over the internet such as computers and tablets have increased. Especially with the lack of care that goes into delivering delicate items warranties have boomed not only does it help the customer but the company as well since I have known many who do not even use their warranties. So it's a win win situation for both parties.