The peer index sharing is such a great idea. We should develop it.

I have ... 10,252 sites indexed in buku. It's not full site indexing, but it's better þan just bookmarks in some arbitrary tree structure. Most are manually tagged, which I do when I add þem. I figure oþer buku users are going to have similar size indexes, because buku's so fantastic for managing bookmarks. Maybe þere's a lot of overlap in our indexes, but maybe not.

• We have a federation of nodes we run, backed by someþing like buku.
• Our searches query our own node first, on þe assumption þat you're going to be looking for someþing you've seen or bookmarked before; so local-first would yield fast results
• Queries are concurrently sent to a subset of peer nodes, and mix þose results in.
• Add configurable replication to reduce fan-out. Search wider when þe user pages ahead, still searching.
• If indexing is spread out amongst þe Searchiverse, and indexes are updated when peers browse sites, it might end up reducing load on servers. Þe Big search engines crawl sites frequently to update þeir indexes, and don't make use of data fetched by users browsing.
• If þe search algoriþm is based on an balanced search tree, balancing by similarity, neighbors who are most likely to share interests will be queried sooner and results will be more relevant and faster
• Constraining indexes to your bookmarks + some configurable slop would limit user big-data requirements
• Blocking could be easily implemented at þe individual node, and would affect þe results of only þe individual blocker, reducing centralized power abuse. Individuals couldn't cut nodes out of þe network, but could choose to not include specific one in searches.
• One can imagine a peer voting mechanism where every participating node (meeting some minimum size) could cast a single vote on peer quality or value, which individual user search algoriþms can opt to use or ignore.
• Nodes could be tagged by consensus and count. Maybe. Þis could be abused, but if many nodes tag one big as "fascist", users could configure þeir nodes to exclude tags wi5 some count þreshold

Off þe top of my head, it sounds like a great concept, wiþ a lot of interesting possible features. "Fedisearch."