This trend began an arms race between the PTS companies who built fraud-prevention software to avoid such exploitation of the model, and fraud program developers attempting to find flaws in this software, where each would release increasingly sophisticated versions of their software. However, by late 2001 with the dot-com bubble's collapse, very few PTS companies remained, as their sole revenue source was internet advertising. The few surviving PTS companies mostly operate on a rewards-based structure where users surf the web or do tasks such as answering marketing email and shopping at specific stores to obtain reward points that can be exchanged for gifts. One version rehashed the concept as "pay-you-for-your-attention" scheme wherein an Internet user is paid in exchange for the surfing interruption or paid in exchange for information about themselves and their Internet habits. A web browser called Brave offered income-sharing feature with its users who opt to view its advertisements. It was designed by JavaScript creator Brendan Eich and Brian Bondy. Brave also proposed an alternate way of compensation for browsing, as users were given tokens, promised that they will eventually be exchangeable for dollars, operating in a similar manner to cryptocurrency. See also Adware Affiliate marketing Basic Attention Token Browser toolbar Cost per impression Paid to click Pay per click References American advertising slogans Business models Dot-com bubble Online advertising 1999 neologisms