Without a doubt, one of the most popular activities on the web is shopping. The one-click convenience makes it incredibly easy to buy stuff without ever getting off your couch.

With giants like eBay and Amazon driving some of the earliest innovation on the web, ecommerce was long predicted to be one of the greatest disruptions of the web.

But sites like Amazon try to provide a solution for nearly every product, and therefore can't offer up a custom or focused experience for very specific products or shoppers. Today, a number of niche sites are creating new kinds of shopping experiences that change the way people discover products. Here are just a few of them that we can learn something from:

Brayola – Using Crowdsourcing And Algorithms For Bra Shopping

This site helps women find their next favorite bra. The lingerie market — valued at over $30 billion — certainly isn't small, but an ecommerce site that focuses on just that market could certainly fit the description.

Brayola looks to a crowdsourced model and smart algorithms to help women find a perfect fitting bra. Brayola is aiming to bring some of the same recommendation innovation that other startups, such as Pandora, have brought to other industries.

Here's how it works: The service asks women to share a few of their favorite bras. It then compares their choices to those of other users on the platform. Like other recommendation platforms, if two users have the same taste in bras — not only style, but more importantly, size — then the platform can recommend new bras based on their preferences.

This site is not only focused on a very specific audience, but a very personal and intimate product as well. What's unique about Brayola is the idea that service can use technology to help women find bras that they will love. Users can find and purchase a wide variety of brands. The unique system the service uses to match up users with new bras helps users overcome the fear of buying something online, which is always the impediment to a new ecommerce platform.

Warby Parker – Finding The Right Sunglasses From Home

This online sunglasses company faced a unique challenge in that sunglasses are a very personal item and most users choose to try them on before purchasing. So how did it overcome this challenge? By sending users several glasses at once to try on at home. The user simply needed to keep the pair they wanted and send the rest back.

This unique solution was perfectly fitted for the company's needs and represents a growing trend in the ecommerce space — finding unique ways of selling a product in order to cater to niche markets.

Harry's – Cutting Out The Middlemen To Save Customers Money

To stand out among competitors, this online seller of men's razors and shaving gear focused on cost efficiencies it could provide compared to traditional retailers.

Its unique selling point is that, by cutting out the supply chain and the costs added by retailers and wholesalers, it can provide a better product at a lower price. It's a classic sales pitch, but the company has certainly been able to use the wide platform that the web provides to turn into a successful ecommerce business.

In addition, its laser focus on one market allows it to hone its messages and service to provide the best experience possible.

ThinkGeek – Catering To A Very Specific Audience

The company provides a wide variety of items — all of them themed for the company's specific audience. This is a classic example of finding a market, and building whatever product happens to appeal to them.

With ThinkGeek, it is often the humor of the item that makes it successful. In fact, many of the company’s most popular products began as April Fool's jokes. This is certainly one of the most unique methods of market research out there.

What all of these sites share is focus — and this allows these smaller services to compete with the do-it-all giants. This is a powerful lesson and can certainly be applied to other industries.

Jet – Reinventing The Shopping Club

The startup, which has raised $225 million and is launching tomorrow, charges consumers a yearly membership fee in order to purchase items at the lowest price available online. It has its own warehouses for big-brand items, but also works to connect users to local stores such as Toys"R"Us and Dick's in order to help them find the best online price.

The most unique aspect of its shopping club experience is the real-time dynamic pricing. Based on the number of items in a shopper's basket, Jet engineers constantly recalculate which seller is able to send the full order most efficiently and inexpensively. This allows for customers to gravitate toward the most economically efficient combination of items, at a minimal inconvenience.

Even though Jet's focus may not be niche, the way it is revolutionizing the ecommerce experience certainly is.

What do you think? What smaller ecommerce site do you believe is pushing the space forward? Let me know in the comments.