The Plaid Python SDK by Plaid allows to interact with the API to implement banking and financial features into web services. Documentation includes code to add user, upgrade accounts, and get transactions.
Stripe, ever aimed at simplifying and increasing web-enabled payment options, has expanded the Stripe API to programmatically send bank transfers to anyone with a US bank account.
One of the many frustrations that mashup developers (and web developers in general) run into is trying to use contextual ads for sites with lots of dynamic content. By their very nature, mashups typically tap into data that constantly changes, making it difficult to use contextual ads that stay up-to-date with content.