Generally, a person in the business of providing compensated investment advisory services is an “investment adviser” in the eyes of state and federal regulators. Your investment activities vis-à-vis the AngelList platform (e.g., identifying portfolio investments for funds, accepting management fees and carry, etc.) position you squarely within the definition of an "investment adviser."
In the U.S. investment advisers may be subject to costly and onerous registration requirements (e.g., periodic financial statement audits). However, many investment advisers can take advantage of exemptions from registration (and these additional obligations) available to “exempt reporting advisers” (ERAs). ERAs are investment advisers that adhere to certain minimum requirements and file ongoing regulatory reports about their activities and funds.
Filing for an exemption as an ERA requires submitting a truncated Form ADV through FINRA. Annually this form must be amended to report on the ERA's activities and funds. Additionally, various compliance requirements must be adhered to as dictated by state and federal law. More information about these requirements is available here.
A Central Registration Depository (CRD) number is provided for an ERA once a Form ADV is submitted through FINRA. To lookup your CRD number (and previous Form ADV filings), you can search for the entity you filed for via the Investment Adviser Public Disclosure website.