AI 瀏覽器來了：Dia 與 Perplexity Comet 是什麼？跟 Chrome 加擴充差在哪

You may have already gotten used to opening Chrome and another ChatGPT page, copying and pasting back and forth whenever you have a question. However, a clear trend has emerged in 2026: to eliminate this back-and-forth action by integrating AI directly into the browser. Two notable examples are Dia and Comet.

Dia: Arc team puts AI in the address bar

Dia is developed by The Browser Company, the same team behind the Arc browser. It integrates an AI assistant directly into the address bar and tabs: you can select text on a webpage and ask questions, or open multiple tabs and ask it to "organize the key points from these pages into a comparison table".

The focus is on "seamlessness". You no longer need to switch windows, and the AI is at your fingertips while browsing, which can save a significant amount of time spent on switching between windows for people who conduct research, compare prices, or search for data online all day.

Comet: Perplexity enables the browser to act on your behalf

Comet is an AI browser developed by Perplexity, which brings Perplexity's expertise in "instant search + source citation" into the browser and adds a key capability: proxy operation. This means it not only answers your questions but can also perform tasks on your behalf across multiple websites, such as reading multiple tabs and organizing them into a summary with sources, after you grant permission.

How is this different from using AI extensions in Chrome?

The difference lies in the "depth of integration". Extensions are add-ons to the browser, which have limited access to information and functionality, often requiring you to copy and paste text; whereas AI browsers are designed with AI at their core, allowing them to understand your entire browsing context across tabs, providing a more seamless experience. To illustrate the difference: extensions are like aftermarket car recorders, while AI browsers are like built-in dashboards.

Proxy operation: convenient, but boundaries need to be set

Comet's ability to "act on your behalf" is the most attractive feature, but also requires caution. Once you allow AI to operate on your behalf on websites, it raises concerns about account permissions and data security. The principle is simple: grant the minimum necessary permissions, and always reserve human confirmation for sensitive actions like payments, password changes, or sending emails.

Should you switch now?

Not necessarily. Both Dia and Comet are still young, and their ecosystems and compatibility are still developing. The recommended approach is to take a common online task you perform daily, such as organizing key points from several news tabs, and try it out for a week to see how much time "built-in AI" can save you. If you feel the difference, you can consider switching; otherwise, you can continue using your Chrome without any drawbacks.