Get ready to say goodbye to unlimited Internet access.
Last week, Comcast -- the second-largest Internet service provider in the country -- announced that starting Oct. 1 it would officially set a threshold for monthly Internet usage.
In an online announcement, the service provider said that although it already contacts residential customers who use excessive amounts of bandwidth, it had never provided a specific limit. Now, Comcast said it will amend its user agreement to say that users will be allowed 250 gigabytes of monthly usage.
The company emphasizes that its cap is generous and will only affect about 1 percent of its 14.4 million customers. Experts say these customers might include heavy gamers and those who use a significant amount of bandwidth for creating or uploading video.
But industry watchers note that Comcast's decision is indicative of a trend by Internet service providers to move toward usage-based service plans.
On Aug. 1, Frontier Communications changed its policy to define acceptable use for high-speed Internet as 5 GB per month. In June, Time Warner Cable launched a test program in Beaumont, Texas, that imposes monthly Internet usage limits of 5 GB to 40 GB on subscribers.
Because Comcast is a heavyweight in the industry, its announcement has drawn criticism and questions from broadband and telecommunications researchers.
"The biggest problem I have [is] they haven't given us any data. They've given us no proof," said Om Malik, author of "Broadbandits: Inside the $750 Billion Telecom Heist" and editor of GigaOM, a popular technology Web site. Malik said GigaOm and five other technology news sites managed by his online publishing company, Giga Omni Media, receive about two million visitors each month.
Comcast's limit is substantially higher that those established by other service providers, Malik acknowledges. But he maintains that the company's decision amounts to metered billing and, if that's the case, it should provide a tool so that consumers can monitor their own usage.
"[With] electricity companies -- and water companies -- you have the choice to monitor the electricity you are using," said Malik, drawing comparisons between Comcast and regulated public utilities that maintain the infrastructure for public services.
"If they are going to behave like a utility, shouldn't they be treated like one?" he added.
He also argued that even though a 250 GB bandwidth cap is generous in today's terms, it may not be sufficient in the future, especially as bandwidth-needy, high-definition video becomes more common.
In its announcement, Comcast said its average residential customer uses approximately 2 to 3 GB. To put its monthly limit of 250 GB in perspective, the company said that to consume that much bandwidth a customer would have to send 50 million e-mails, 62,500 songs, download 125 standard-definition movies or upload 25,000 hi-resolution digital photos.
Comcast spokesman Charlie Douglas told ABCNews.com that the company has had an excessive use policy for years but has never disclosed its definition of excessive use.