For many in the dotcom world, 2007 was dominated by one story: the rise of Facebook. The success of the social networking service has increased optimism about the internet industry. After all, if Microsoft is prepared to buy a 1.6% share for $240m (£121m), there is evidence that good ideas can be worth a lot of money. It is no surprise then that investors are looking for the next big thing - and these are some of the favourites.

The New York-based internet retailer says it is "your place to buy and sell all things handmade". Where Amazon revolutionised online commerce and eBay made its name allowing people to sell off their unwanted possessions, Etsy hopes to tap into the trend for hand-crafted and personalised items.

With thousands of craftspeople selling everything from clothes and ceramics to jewellery, the site has quickly become an Aladdin's Cave of the internet.

Its innovative sales approach - such as letting shoppers browse by colour, or allowing geographical searches to support local suppliers - has drawn a legion of followers. Etsy now has more than half a million registered users and 60,000 sellers.

Founded by 27-year-old Robert Kalin from Boston, the site was launched in 2005 and now has more than 40 staff in New York and San Francisco.

Some critics find it a contradiction - a mass market dedicated to niche products - but Kalin says: "Etsy is a distribution platform for any kind of content that isn't mass produced ... not just craft-based, it might include music."

Twitter lets you text message large groups of people simultaneously, and for free. Sign up and send it a message - from a phone, internet or instant messaging service - and it will be sent to your contacts.

Updates are limited to just 140 characters, leading Twitter's creators to call it "microblogging". The craze caught on with the technology cognoscenti in 2007, but many pundits expect it to now reach out to the mainstream.

Some say it is a simple way of keeping a connection with friends and family, regardless of time and distance.

"Twitter is about the intimacy of details," said author David Weinberger. "Through it I see small events in the lives of friends about whom I otherwise might only learn the big events when we catch up after long intervals."

Crucially, it has also been picked up by businesses as an easy way to push messages out to their customers.

Co-founder Ev Williams helped popularise blogging with Blogger.com before selling it to Google in 2002.

With Facebook so prominent in 2007, many copycat services are expected in the next few months. But Dopplr.com is trying to find a different angle. Aimed at frequent travellers, the site lets users keep track of where their friends and colleagues are and enables them to meet up in unexpected places - or keep tabs on who is visiting their home town in the next few days.

The site had a public launch this month. During the test phase the audience was limited to international jet-setters and conference veterans, but thanks to a series of canny features - including integration into Facebook - it is ready to break out and gather many more users.

The site, founded by an international team of web technologists, is run from an office in Hoxton, in east London. This year two of its masterminds, Matt Biddulph and Matt Jones, were named among the capital's most influential people.

Jimmy Wales, co-founder of Wikipedia, has said it is his favourite website. "You put in your travel schedule and link to your friends. It allows you to see where everyone is. I love it," he told the New York Times.

Mike Butcher, the editor of startup news website Techcrunch UK, said Moshi Monsters is "Tamagotchi meets Facebook for 7-12 year olds, but with education thrown in". Created by London games firm Mind Candy, Moshi Monsters takes the idea of virtual pet games such as Nintendogs, and adds the concepts of social networking and puzzles.

Players "adopt" a monster by buying a small charm which gives them an access code to the website. They then pick their monster, and look after them by solving regular puzzles. Monsters can interact with each other online, providing a socialising aspect for children with strict systems in place to keep players safe. With its cartoon graphics and addictive qualities, Moshi wants to become the next craze for UK children - and has plans to launch in Europe and the US.

The site is going through testing but the so-called "tween" market can be incredibly lucrative. Club Penguin, a children's virtual world started two years ago, was bought by Disney this year for $350m.

Since Google bought YouTube two years ago, a slew of video sites have arrived on the web. One to watch could be Seesmic. While YouTube has become dominated by spoofs, skits and professional marketing videos, Seesmic hopes to recapture the spirit of those who first made the site a success: people who want to put video diaries on the internet.

Focused on short webcam "conversations" between individuals, the site has not gone public yet, but has had positive reviews from testers and could become the home for a generation of opinionated, attention-seeking web surfers.

It is backed by Ron Conway, an early investor in Google and PayPal, and European entrepreneurs Niklas Zennstrom and Janus Friis, responsible for Kazaa, Skype and internet TV company Joost.

When it does go public, the site hopes to plug into other hugely popular websites - such as MySpace and Facebook - rather than replace them.

It was founded by a French entrepreneur, Loic Le Meur. The businessman and blogger is known for his brash style, but it is his role as an internet adviser to the French president, Nicolas Sarkozy, that could lend most weight to the site.