I’ve gotten the bot-like improvements I wanted thanks to these snippets of elisp code:

(require 'hippie-exp)

(setq hippie-expand-try-functions-list
      '(sacha/try-expand-factoid-from-bbdb
        try-complete-file-name
        try-expand-all-abbrevs
        try-expand-dabbrev-from-kill
        try-expand-dabbrev-visible
        try-expand-dabbrev-all-buffers))

;; Particularly fun with ERC. I am now a bot!
(defun sacha/try-expand-factoid-from-bbdb (old)
  "Try to expand from BBDB. If OLD is non-nil, cycle through other possibilites."
  (unless old
      ;; First time, so search through the BBDB records for the factoid.
    (progn
      (he-init-string (he-dabbrev-beg) (point))
      (setq he-expand-list nil)
      (mapc
       (lambda (item)
         (setq he-expand-list (append he-expand-list (list (bbdb-record-getprop item 'blog))))
         (setq he-expand-list (append he-expand-list (list (bbdb-record-getprop item 'web))))
         (setq he-expand-list (append he-expand-list (list (car (bbdb-record-net item)))))
         (setq he-expand-list (append he-expand-list (list (bbdb-record-getprop item 'notes)))))
       (bbdb-search (bbdb-records) he-search-string he-search-string he-search-string he-search-string nil))
      (setq he-expand-list (delq nil he-expand-list))))
  (while (and he-expand-list
              (or (not (car he-expand-list))
                  (he-string-member (car he-expand-list) he-tried-table t)))
    (setq he-expand-list (cdr he-expand-list)))
  (if (null he-expand-list)
      (progn
        (if old (he-reset-string))
        nil)
    (progn
      (he-substitute-string (car he-expand-list) t)
      (setq he-expand-list (cdr he-expand-list))
      t)))

hippie-expand inside an ERC buffer will then cycle through the blog, web, net and notes fields of whatever entries I have. Yay! =)